/*模拟数据库数据*/
var cities = [
    {
        id: 1,
        name: '天津',
        areas:[
            {
                id:11,
                name:'河西区'
            },{
                id:12,
                name:'和平区'
            }
        ]
    }, {
        id: 2,
        name: '北京',
        areas:[
            {
                id:21,
                name:'朝阳区'
            },{
                id:22,
                name:'宣武区'
            }
        ]
    }
]